Organic light-emitting diode display

ABSTRACT

An organic light-emitting diode (OLED) display includes a substrate, an auxiliary electrode disposed on the substrate, a first signal line disposed on the substrate, a second signal line crossing the first signal line, a driving voltage line disposed on the substrate, a first thin film transistor connected to the first signal line and the second signal line, a second thin film transistor connected to the first thin film transistor and the driving voltage line, a first electrode connected to the second thin film transistor, a second electrode facing the first electrode, and a light-emitting member disposed between the first electrode and the second electrode. The auxiliary electrode is connected to one of the driving voltage line and the second electrode.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of Korean PatentApplication No. 10-2005-0109063, filed on Nov. 15, 2005, and is acontinuation-in-part of application Ser. No. 11/204,042, filed on Aug.16, 2005, which is a continuation of application Ser. No. 10/732,280,filed on Dec. 11, 2003, now issued as U.S. Pat. No. 6,946,791, whichclaims priority from and the benefit of Korean Patent Application No.10-2002-0078744, filed on Dec. 11, 2002, which are incorporated byreference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organic light-emitting diode (OLED)display and a manufacturing method thereof.

2. Discussion of the Background

The recent trend toward lightweight and thin personal computers andtelevision sets requires lightweight and thin display devices. Hence,flat panel displays are replacing conventional cathode ray tubes (CRT).Flat panel displays include a liquid crystal display (LCD), a fieldemission display (FED), an organic light-emitting diode (OLED) display,and a plasma display panel (PDP). Among flat panel displays, the OLEDdisplay is the most promising because of its low power consumption, fastresponse time, wide viewing angle, and high contrast ratio. An OLEDdisplay is a self-emissive display device that includes an organiclight-emitting layer interposed between two electrodes. One electrodeinjects holes and the other injects electrons into the light-emittinglayer. The injected electrons and holes combine to form exitons, whichemit light as they discharge energy. An OLED display may be a passivematrix display or an active matrix display according to its drivingmethod. The passive matrix OLED display includes a plurality of anodelines, a plurality of cathode lines crossing the anode lines, and aplurality of pixels, each including a light emission layer. Selectingone anode line and one cathode line causes light emission of the pixellocated at the intersection of the selected signal lines. The activematrix OLED display includes a plurality of pixels, and each pixel mayinclude a switching transistor, a driving transistor, and a storagecapacitor, as well as an anode, a cathode, and a light emission layer.The driving transistor receives a data voltage from the switchingtransistor and drives a current having a magnitude corresponding to thedata voltage. The current from the driving transistor enters the lightemission layer to cause light to emit at an intensity that depends onthe current.

Here, input terminals of the driving transistors are commonly connectedto driving voltage lines, which supply a driving voltage to therespective driving transistors. Hence, the magnitude of the currentflowing through each driving transistor may be defined by the drivingvoltage as well as the data voltage. In other words, the magnitude ofthe current may be defined by a difference between the driving voltageand the data voltage.

However, with a larger OLED display, the driving voltages applied to therespective driving transistors may not be uniform. Therefore, when datavoltages of equal magnitude are applied to the driving transistors, thedriving transistors may not output equal driving currents due to voltagedrop, etc. Consequently, the same data voltage may result in differentgray scales for displaying images.

Accordingly, a difference between driving voltages due to voltage dropmay cause cross-talk, which deteriorates image quality.

SUMMARY OF THE INVENTION

The present invention provides a display device that may provide asubstantially uniform driving voltage and/or common voltage.

Additional features of the invention will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention.

The present invention discloses an organic light-emitting diode (OLED)display that includes a substrate, an auxiliary electrode disposed onthe substrate, a first signal line disposed on the substrate, and asecond signal line crossing the first signal line. A driving voltageline is disposed on the substrate, a first thin film transistor isconnected to the first signal line and the second signal line, and asecond thin film transistor is connected to the first thin filmtransistor and the driving voltage line. A first electrode is connectedto the second thin film transistor, a second electrode faces the firstelectrode, and a light-emitting member is disposed between the firstelectrode and the second electrode. The auxiliary electrode is connectedto at least one of the driving voltage line and the second electrode.

The present invention also discloses an OLED display that includes asubstrate, a first auxiliary electrode disposed on the substrate, afirst signal line disposed on the substrate, and a second signal linecrossing the first signal line. A driving voltage line is connected tothe first auxiliary electrode, a first thin film transistor is connectedto the first signal line and the second signal line, and a second thinfilm transistor is connected to the first thin film transistor and thedriving voltage line. A first electrode is connected to the second thinfilm transistor, a second electrode faces the first electrode, and alight-emitting member is disposed between the first electrode and thesecond electrode.

The present invention also discloses an OLED display, that includes asubstrate, an auxiliary electrode disposed on the substrate, a firstsignal line disposed on the substrate, and a second signal line crossingthe first signal line. A first thin film transistor is connected to thefirst signal line and the second signal line, and a second thin filmtransistor is connected to the first thin film transistor. A firstelectrode is connected to the second thin film transistor, a secondelectrode faces the first electrode and is connected to the auxiliaryelectrode, and a light-emitting member is disposed between the firstelectrode and the second electrode.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is an equivalent circuit diagram of an OLED display according toexemplary embodiments of the present invention.

FIG. 2 is a layout view of an OLED display according to a firstexemplary embodiment of the present invention.

FIG. 3 and FIG. 4 are sectional views of the OLED display of FIG. 2taken along lines III-III and IV-IV, respectively.

FIG. 5, FIG. 8, FIG. 1, and FIG. 14 are layout views of the OLED displayof FIG. 2, FIG. 3, and FIG. 4 showing intermediate steps of amanufacturing method thereof according to a first exemplary embodimentof the present invention.

FIG. 6 and FIG. 7 are sectional views of the OLED display of FIG. 5taken along lines VI-VI and VII-VII, respectively.

FIG. 9 and FIG. 10 are sectional views of the OLED display of FIG. 8taken along lines IX-IX and X-X, respectively.

FIG. 12 and FIG. 13 are sectional views of the OLED display of FIG. 1taken along lines XII-XII and XIII-XIII, respectively.

FIG. 15 and FIG. 16 are sectional views of the OLED display of FIG. 14taken along lines XV-XV and XVI-XVI, respectively.

FIG. 17 and FIG. 18 are layout views of an OLED display according to asecond exemplary embodiment of the present invention.

FIG. 19 is a layout view of an OLED display according to a thirdexemplary embodiment of the present invention.

FIG. 20 is a sectional view of the OLED of FIG. 19 taken along lineXX-XX.

FIG. 21 is a layout view of an OLED display according to a fourthexemplary embodiment of the present invention.

FIG. 22 is a sectional view of the OLED of FIG. 21 taken along lineXXII-XXII.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The present invention will now be described more fully hereinafter withreference to the accompanying drawings, in which exemplary embodimentsof the invention are shown. As those skilled in the art would realize,the described embodiments may be modified in various ways, all withoutdeparting from the spirit or scope of the invention. Therefore, thisinvention should not be construed as limited to the embodiments setforth herein. Rather, these embodiments are provided so that thisdisclosure is thorough, and will fully convey the scope of the inventionto those skilled in the art.

In the drawings, the size and relative sizes of layers, films, panels,regions, etc., may be exaggerated for clarity. Like reference numeralsdesignate like elements throughout the specification. It will beunderstood that when an element such as a layer, film, region, orsubstrate is referred to as being “on” or “connected to” anotherelement, it can be directly on or directly connected to the otherelement or intervening elements may also be present. In contrast, whenan element is referred to as being “directly on” or “directly connectedto” another element, there are no intervening elements present.

FIG. 1 is an equivalent circuit diagram of an OLED display according toexemplary embodiments of the present invention.

Referring to FIG. 1, the OLED display includes a plurality of signallines 121, 171, and 172. A plurality of pixels PX are connected to thesignal lines 121, 171, and 172 and arranged substantially in a matrix.

The signal lines include a plurality of gate lines 121, which transmitgate signals (or scanning signals), a plurality of data lines 171, whichtransmit data signals, and a plurality of driving voltage lines 172,which transmit a driving voltage. The gate lines 121 extendsubstantially in a row direction and substantially parallel to eachother, while the data lines 171 and the driving voltage lines 172 extendsubstantially in a column direction and substantially parallel to eachother.

Each pixel PX includes a switching transistor Qs, a driving transistorQd, a capacitor Cst, and an OLED LD.

The switching transistor Qs has a control terminal connected to a gateline 121, an input terminal connected to a data line 171, and an outputterminal connected to the driving transistor Qd. The switchingtransistor Qs transmits the data signals applied to the data line 171 tothe driving transistor Qd in response to the gate signal applied to thegate line 121.

The capacitor Cst is connected between the control terminal and theinput terminal of the driving transistor Qd. The capacitor Cst storesthe data signal applied to the control terminal of the drivingtransistor Qd and maintains the data signal after the switchingtransistor Qs turns off.

The OLED LD has an anode connected to the output terminal of the drivingtransistor Qd and a cathode connected to a common voltage Vss. The OLEDLD emits light having an intensity depending on an output current ILD ofthe driving transistor Qd, thereby displaying images.

The switching transistor Qs and the driving transistor Qd are n-channelfield effect transistors (FETs). However, at least one of the switchingtransistor Qs and the driving transistor Qd may be a p-channel FET.Additionally, the connections among the transistors Qs and Qd, thecapacitor Cst, and the OLED LD may be modified.

A detailed structure of the OLED display of FIG. 1 according to anexemplary embodiment of the present invention will be described indetail below with reference to FIG. 2, FIG. 3, and FIG. 4.

FIG. 2 is a layout view of an OLED display according to a firstembodiment of the present invention, and FIG. 3 and FIG. 4 are sectionalviews of the OLED display of FIG. 2 taken along lines III-III and IV-IV,respectively.

An auxiliary electrode 111 is formed on an insulating substrate 110,which may be made of a material such as transparent glass or plastic.The auxiliary electrode 111 may have a substantially planar shape, andit may cover the entire a mother substrate (not shown). When the OLEDdisplay is a bottom emission type, the auxiliary electrode 111 may bemade of a transparent or translucent conductor such as indium tin oxide(ITO) or indium zinc oxide (IZO), etc. Alternatively, when the OLEDdisplay is a top-emission type, the auxiliary electrode 111 may be madeof a low resistivity conductor including Al, Ag, Cu, or alloys thereof.

A blocking layer 112, which may be made of silicon nitride (SiNx) orsilicon oxide (SiOx), etc., is formed on the auxiliary electrode 111.

A plurality of gate conductors that include a plurality of gate lines121 and a plurality of second control electrodes 124 b are formed on theblocking layer 112. The gate lines 121 include first control electrodes124 a.

The gate lines 121 transmit gate signals and extend substantially in atransverse direction. Each gate line 121 further includes an end portion129, which has a large area for connecting to another layer or anexternal driving circuit, and the first control electrodes 124 a, whichproject upward from the gate line 121. The gate lines 121 may extend tobe directly connected to a gate driving circuit (not shown) forgenerating the gate signals, which may be integrated on the substrate110.

Each second control electrode 124 b is spaced apart from the gate lines121 and includes a storage electrode 127, which extends downward fromthe second control electrode 124 b, turns to the right, and extendsupward as shown in FIG. 2.

The gate conductors 121 and 124 b may be made of Al, Ag, Cu, Mo or analloy thereof, Cr, Ta, Ti, etc. The gate conductors 121 and 124 b mayhave a multi-layered structure including two films having differentphysical characteristics from each other.

The lateral sides of the gate conductors 121 and 124 b are inclined atan angle ranging from about 30 to 80 degrees relative to a surface ofthe substrate 110.

A gate insulating layer 140, which may be made of silicon nitride (SiNx)or silicon oxide (SiOx), is formed on the gate conductors 121 and 124 b.The gate insulating layer 140 and the blocking layer 112 have aplurality of contact holes 147 exposing portions of the auxiliaryelectrode 111.

A plurality of first and second semiconductor islands 154 a and 154 b,which may be made of hydrogenated amorphous silicon (“a-Si”) orpolysilicon, are formed on the gate insulating layer 140. The first andsecond semiconductor islands 154 a and 154 b are disposed on the firstand second control electrodes 124 a and 124 b, respectively.

A plurality of pairs of first ohmic contact islands 163 a and 165 a anda plurality of pairs of second ohmic contact islands 163 b and 165 b areformed on the first and the second semiconductor islands 154 a and 154b, respectively. The ohmic contacts 163 a, 163 b, 165 a, and 165 b maybe made of silicide or n+ hydrogenated a-Si heavily doped with an n-typeimpurity such as phosphorous.

A plurality of data conductors, which include a plurality of data lines171, a plurality of driving voltage lines 172, and a plurality of firstand second output electrodes 175 a and 175 b, are formed on the ohmiccontacts 163 a, 163 b, 165 a, and 165 b and the gate insulating layer140.

The data lines 171, which transmit data signals, extend substantially inthe longitudinal direction and cross the gate lines 121. Each data line171 includes a plurality of first input electrodes 173 a extendingtoward the first control electrodes 124 a and an end portion 179, whichhas a large area for connecting to another layer or an external drivingcircuit. The data lines 171 may extend to be directly connected to adata driving circuit (not shown) for generating the data signals, andthe data driving circuit may be integrated on the substrate 1110.

The driving voltage lines 172, which transmit driving voltages, extendsubstantially in the longitudinal direction and cross the gate lines121. Each driving voltage line 172 includes a plurality of second inputelectrodes 173 b extending toward the second control electrodes 124 b.The driving voltage lines 172 overlap the storage electrodes 127.

The driving voltage lines 172 are connected to the auxiliary electrode111 through the contact holes 147. The driving voltage lines 172 and theauxiliary electrode 111 are supplied with the same voltage.Consequently, driving voltages applied to the pixels may besubstantially equal to each other. Moreover, although the auxiliaryelectrode 111 has sheet resistance, and a voltage applied to theauxiliary electrode 111 drops due to surface resistance, voltagesapplied to the respective pixels may be almost uniformly maintained.Therefore, substantially uniform voltages may be applied to the pixelssuch that image deterioration, such as a cross-talk due to a luminancedifference of pixels, largely decreases.

The first and second output electrodes 175 a and 175 b are spaced apartfrom each other and from the data lines 171 and the driving voltagelines 172. Each pair of a first input electrode 173 a and a first outputelectrode 175 a are disposed opposing each other with respect to a firstcontrol electrode 124 a, and each pair of a second input electrode 173 band a second output electrode 175 b are disposed opposing each otherwith respect to a second control electrode 124 b.

The data conductors 171, 172, 175 a, and 175 b may be made of arefractory metal including Mo, Cr, Ta, Ti, or alloys thereof. They mayhave a multi-layered structure including a refractory metal film and alow resistivity film.

Similar to the gate conductors 121 and 124 b, lateral sides of the dataconductors 171, 172, 175 a, and 175 b are inclined at an angle rangingfrom about 30 to 80 degrees relative to a surface of the substrate 110.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175 b, the exposed portions of the semiconductor islands 154 aand 154 b, and the gate insulating layer 140.

The passivation layer 180 may be made of an inorganic or organicinsulator, and it may have a substantially flat top-surface. Examples ofthe inorganic insulator include silicon nitride and silicon oxide, andan example of the organic insulator includes a polyacryl. Thepassivation layer may include two or more layers. For example, thepassivation layer 180 may have a double-layered structure including alower film of an inorganic insulator and an upper film of an organicinsulator.

The passivation layer 180 has a plurality of contact holes 182, 185 a,and 185 b exposing the end portions 179 of the data lines 171, the firstoutput electrodes 175 a, and the second output electrodes 175 b,respectively, and the passivation layer 180 and the gate insulatinglayer 140 have a plurality of contact holes 181 and 184 exposing the endportions 129 of the gate lines 121 and the second control electrodes 124b, respectively.

A plurality of pixel electrodes 191, a plurality of connecting members85, and a plurality of contact assistants 81 and 82 are formed on thepassivation layer 180.

The pixel electrodes 191 are connected to the second output electrodes175 b through the contact holes 185 b.

The connecting members 85 are connected to the second control electrodes124 b and the first output electrodes 175 a through the contact holes184 and 185 a, respectively.

The contact assistants 81 and 82 are connected to the end portions 129of the gate lines 121 and the end portions 179 of the data lines 171through the contact holes 181 and 182, respectively. The contactassistants 81 and 82 protect the end portions 129 and 179 and enhanceadhesion between the end portions 129 and 179 and external devices.

A partition 361 is formed on the passivation layer 180 to form a bankaround the pixel electrodes 191, thereby defining openings 365. Thepartition 361 may be made of an organic material having thermalresistance and solvent resistance such as acrylic resin or polyimideresin, etc., or an inorganic insulating material such as SiO₂ or TiO₂,etc. The partition 361 may be made of a photosensitive materialcontaining a black pigment so that the black partition 361 may serve asa light blocking member and it may be more easily formed.

A plurality of organic light-emitting members 370 are formed on thepixel electrodes 191. The organic light-emitting members 370 may beconfined in the openings 365 defined by the partition 361.

Each organic light-emitting member 370 may have a multi-layeredstructure including a light emitting layer (not shown), which emitslight, and one or more auxiliary layers (not shown), which improve thelight-emitting layer's light emission efficiency.

The light-emitting layers may be made of an organic material or amixture of an organic material and an inorganic material that emitslight of one primary color such as red, green, or blue, or thelight-emitting layers may include a compound doped with a polyfluorenederivative, a (poly)paraphenylenevinylene derivative, a polyphenylenederivative, a polyfluorene derivative, polyvinylcarbazole, apolythiophene derivative, or a compound made by adding aperylene-containing pigment, a cumarine-containing pigment, a rhodaminegroup pigment, rubrene, perylene, 9,10-diphenylanthracene,tetraphenylbutadiene, Nile red, coumarin, quinacridone, etc., to a highpolymer of the derivatives. The OLED display displays images byspatially adding the monochromatic primary color lights emitted from thelight-emitting layers.

The auxiliary layers (not shown) may include an electron transport layer(ETL) and a hole transport layer (HTL) to improve the balance ofelectrons and holes, and an electron injecting layer (EIL) and a holeinjecting layer (HIL) to improve the injection of electrons and holes.The auxiliary layers may include one or more of such layers. The HTL andthe HIL may be made of a material having a work function having amagnitude that is between that of the pixel electrode 191 and thelight-emitting layer, and the ETL and the EIL may be made of a materialhaving a work function that is between that of a common electrode 270and the light-emitting layers. For instance, the HTL and the HIL mayinclude poly-(3,4-ethylenedioxythiophene:polystyrenesulfonate(PEDOT:PSS), etc.

The common electrode 270 is formed on the organic light-emitting members370 and the partition 361. The common electrode 270 is formed on theentire surface of the organic light-emitting members 370, and it appliesa current to the organic light-emitting member 370 together with thepixel electrodes 191.

In an OLED display such as described above, a first control electrode124 a connected to a gate line 121, a first input electrode 173 aconnected to a data line 171, and a first output electrode 175 a, alongwith a first semiconductor island 154 a, form a switching TFT Qs havinga channel formed in the first semiconductor island 154 a disposedbetween the first input electrode 173 a and the first output electrode175 a. Likewise, a second control electrode 124 b connected to a firstoutput electrode 175 a, a second input electrode 173 b connected to adriving voltage line 172, and a second output electrode 175 b connectedto a pixel electrode 191, along with a second semiconductor island 154b, form a driving TFT Qd having a channel formed in the secondsemiconductor island 154 b disposed between the second input electrode173 b and the second output electrode 175 b.

In the exemplary embodiment of FIG. 1 and FIG. 2, each pixel includes aswitching TFT Qs and a driving TFT Qd, but the pixels may furtherinclude at least one transistor and a plurality of wires for driving thetransistor such that deterioration of the organic light-emitting diodeLD and the driving TFT Qd due to long-time driving is prevented orcompensated, to prevent shortening the life of the OLED.

A pixel electrode 191, an organic light-emitting member 370, and thecommon electrode 270 form an OLED LD having the pixel electrode 191 asan anode and the common electrode 270 as a cathode, or vice versa. Theoverlapping portions of a storage electrode 127 and a driving voltageline 172 form a storage capacitor Cst.

Alternatively, the semiconductor islands 154 a and 154 b may be made ofpolysilicon. In this case, they may include intrinsic regions (notshown) disposed under the gate electrodes 124 a and 124 b and extrinsicregions (not shown) disposed opposing each other with respect to theintrinsic regions. The extrinsic regions are connected to the inputelectrodes 173 a and 173 b and the output electrodes 175 a and 175 b,and the ohmic contacts 163 a, 163 b, 165 a, and 165 b may be omitted.

Further, the gate electrodes 124 a and 124 b may be disposed over thesemiconductor islands 154 a and 154 b, while the gate insulating layer140 is still interposed between the semiconductor islands 154 a and 154b and the gate electrodes 124 a and 124 b. Here, the data conductors171, 172, 173 b and 175 b may be disposed on the gate insulating layer140 and connected to the semiconductor islands 154 a and 154 b throughcontact holes (not shown) in the gate insulating layer 140. Otherwise,the data conductors 171, 172, 173 b, and 175 b may be disposed under thesemiconductor islands 154 a and 154 b and may contact the semiconductorislands 154 a and 154 b.

A method of manufacturing the OLED display shown in FIGS. 2-4 isdescribed below with reference to FIGS. 5-16, as well as FIGS. 2-4,according to an exemplary embodiment of the present invention.

FIG. 5, FIG. 8, FIG. 11, and FIG. 14 are layout views of the OLEDdisplay of FIG. 2, FIG. 3, and FIG. 4 in intermediate steps of amanufacturing method thereof according to an exemplary embodiment of thepresent invention. FIG. 6 and FIG. 7 are sectional views taken alonglines VI-VI and VII-VII of FIG. 5, respectively. FIG. 9 and FIG. 10 aresectional views taken along lines IX-IX and X-X of FIG. 8, respectively.FIG. 12 and FIG. 13 are sectional views taken along lines XII-XII andXIII-XIII of FIG. 11, respectively. FIG. 15 and FIG. 16 are sectionalviews taken along lines XV-XV and XVI-XVI of FIG. 14, respectively.

Referring to FIG. 5, FIG. 6, and FIG. 7, an auxiliary electrode 111,which may be made of a conductor such as ITO, IZO, etc., is formed on asubstrate 110. For example, the auxiliary electrode 111 may be formed bydisposing a shadow mask on the substrate 110 and depositing theconductor. Alternatively, the conductor may be deposited on the entiresurface of the substrate 110 and portions of the conductor on ends ofthe substrate 110 may be removed.

Next, a blocking layer 112, which may be made of silicon nitride, isformed on the auxiliary electrode 111.

Gate conductors that include a plurality of gate lines 121 and aplurality of second control electrodes 124 b are formed on the blockinglayer 112. The gate lines 121 include first control electrodes 124 a andend portions 129, and the second control electrodes 124 b includestorage electrodes 127. The gate conductors are preferably made of an Alalloy.

Referring to FIG. 8, FIG. 9, and FIG. 10, after sequentially depositinga gate insulating layer 140, an intrinsic a-Si layer, and an extrinsica-Si layer on the gate insulating layer 140, the extrinsic a-Si layerand the intrinsic a-Si layer are patterned by photolithography andetched to form a plurality of extrinsic semiconductor islands (notshown) and a plurality of intrinsic semiconductor islands 154 a and 154b.

The gate insulating layer 140 and the blocking layer 112 may bepatterned by photolithography to form a plurality of contact holes 147.

Data conductors that include a plurality of data lines 171, a pluralityof driving voltage lines 172, and a plurality of first and second outputelectrodes 175 a and 175 b are preferably made of an Al alloy. The datalines 171 include first input electrodes 173 a and end portions 179, andthe driving voltage lines 172 include second input electrodes 173 b.Here, the driving voltage lines 172 are connected to the auxiliaryelectrode 111 through the contact holes 147.

Thereafter, portions of the extrinsic semiconductor islands, which arenot covered with the data conductors 171, 172, 175 a, and 175 b, may beremoved by etching to complete a plurality of ohmic contact islands 163a, 163 b, 165 a, and 165 b and to expose portions of the intrinsicsemiconductor islands 154 a and 154 b.

Referring to FIG. 11, FIG. 12, and FIG. 13, a passivation layer 180 isdeposited and patterned by photolithography and etching using chemicalvapor deposition or a printing process to form a plurality of contactholes 181, 182, 184, 185 a and 185 b. The contact holes 181, 182, 184,185 a, and 185 b expose the end portions 129 of the gate lines 121, theend portions 179 of the data lines 171, the second control electrodes124 b, the first output electrodes 175 a, and the second outputelectrodes 175 b, respectively.

Next, referring FIG. 11, FIG. 12, and FIG. 13, a plurality of pixelelectrodes 191, a plurality of connecting members 85, and a plurality ofcontact assistants 81 and 82 are formed on the passivation layer 180.

Referring to FIG. 14, FIG. 15, and FIG. 16, after depositing aphotosensitive organic insulator using spin coating, the insulator isexposed and developed by photolithography to form a partition 361 havingopenings 365 on the pixel electrodes 191.

Thereafter, a plurality of organic light-emitting members 370, each ofwhich includes an HTL (not shown) and a light-emitting layer (notshown), are formed on the pixel electrodes 191 and confined in theopenings 365.

The organic light-emitting members 370 may be formed by a solutionprocess such as an inkjet printing or a deposition process. The organiclight-emitting members 370 may be formed by inkjet printing, whichdeposits a solution into the openings 365 while moving an inkjet head(not shown). In this case, a drying step for removing solvent followsthe deposition process.

Next, referring to FIG. 2, FIG. 3, and FIG. 4, a common electrode 270 isformed on the partitions 361 and the organic light-emitting members 370.

A second exemplary embodiment of the present invention, of whichportions are modified with respect to the above-described firstexemplary embodiment, will be described below with reference to FIG. 17and FIG. 18.

FIG. 17 and FIG. 18 are layout views showing an OLED display accordingto the second exemplary embodiment of the present invention.

Referring to FIG. 17, an auxiliary electrode 111 is formed so that itdoes not overlap the gate lines 121, as opposed to the first exemplaryembodiment in which the auxiliary electrode 111 is formed on the entiresurface of the mother substrate. Not overlapping the auxiliary electrode111 and the gate lines 121 may prevent a short-circuit between theauxiliary electrode 111 and the gate lines 121.

Referring to FIG. 18, the auxiliary electrode 111 is formed between thegate lines 121 and the light-emitting regions, which correspond to thelight-emitting layers of the organic light-emitting members 370. Whenthe above structure is applied, even though the OLED is a bottomemission type, the light-emitting regions are not covered by theauxiliary electrode 111. Hence, the auxiliary electrode 111 may be anopaque conductor. Therefore, when the OLED is the bottom emission type,the auxiliary electrode 111 may be formed of a low resistivity conductorsuch as Al, Ag, Cu, or an alloy thereof, to reduce resistance.

The other elements except for the auxiliary electrode 111 are the sameas those of the first exemplary embodiment. Detailed descriptions of theelements are therefore omitted.

An OLED display of a top-emission type according to a third exemplaryembodiment of the present invention will be described below withreference to FIG. 19 and FIG. 20, as well as FIG. 1. Descriptions of thesame elements as those of the above-described embodiments are omitted.

FIG. 19 is a layout view of an OLED display according to a thirdexemplary embodiment of the present invention, and FIG. 20 is asectional view taken along line XX-XX of FIG. 19.

An auxiliary electrode 111 is formed on an insulating substrate 110. Theauxiliary electrode 111 may have a substantially planar shape, and itmay cover the entire surface of a mother substrate (not shown). Theauxiliary electrode 111 may be made of a low resistivity conductorincluding Al, Ag, Cu, or alloys thereof.

A blocking layer 112 is formed on the auxiliary electrode 111.

A plurality of gate conductors that include a plurality of gate lines121, a plurality of second control electrodes 124 b, and a plurality ofvoltage auxiliary lines 122 are formed on the blocking layer 112. Thegate lines 121 include first control electrodes 124 a, and the voltageauxiliary lines 122 include protrusions 123.

The voltage auxiliary lines 122 transmit a common voltage and extendsubstantially in parallel with the gate lines 121. The protrusions 123extend downward from each auxiliary electrode line 122.

The gate insulating layer 140 is formed on the gate conductors 121, 124b, and 122.

A plurality of first and second semiconductor islands 154 a and 154 bare formed on the gate insulating layer 140. A plurality of pairs offirst ohmic contact islands 163 a and 165 a and a plurality of pairs ofsecond ohmic contact islands 163 b and 165 b are formed on the first andsecond semiconductor islands 154 a and 154 b, respectively.

A plurality of data conductors, which include a plurality of data lines171, a plurality of driving voltage lines 172, and a plurality of firstand second output electrodes 175 a and 175 b, are formed on the ohmiccontacts 163 a, 163 b, 165 a, and 165 b and the gate insulating layer140.

Unlike the above-described embodiments, the driving voltage lines 172are not connected to the auxiliary electrode 111.

Alternatively, instead of forming the voltage auxiliary lines 122 on thesame layer as the gate lines 121, the voltage auxiliary lines may beformed on the same layer as the data lines 171, the driving voltagelines 172, and the first and second output electrode 175 a and 175 b. Inthis case, the voltage auxiliary lines may extend substantially inparallel with the data lines 171.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175 b, the exposed portions of the semiconductor islands 154 aand 154 b, and the gate insulating layer 140.

The passivation layer 180 has a plurality of contact holes 182, 185 a,and 185 b exposing the end portions 179 of the data lines 171, the firstoutput electrodes 175 a, and the second output electrodes 175 b,respectively, and the passivation layer 180 and the gate insulatinglayer 140 have a plurality of contact holes 181, 184, and 186 exposingthe end portions 129 of the gate lines 121, the second controlelectrodes 124 b, and the protrusions 123 of the voltage auxiliary lines122, respectively. Furthermore, the passivation layer 180, the gateinsulating layer 140, and the blocking layer 112 have a plurality ofcontact holes 188 exposing the auxiliary electrode 111.

A plurality of pixel electrodes 191, a plurality of connecting members85 and 86, and a plurality of contact assistants 81 and 82 are formed onthe passivation layer 180.

They may have a single-layered structure, which may be made of an opaqueconductor, or a double-layered structure of ITO and an opaque conductor.The opaque conductor may be made of Al, Au, Pt, Ni, Cu, W, or alloysthereof having a high work function.

The connecting members 85 are connected to the second control electrodes124 b and the first output electrodes 175 a through the contact holes184 and 185 a, respectively.

The connecting members 86 are connected to the protrusions 123 of thevoltage auxiliary lines 122 and the auxiliary electrodes 111 through thecontact holes 186 and 188, respectively.

A partition 361, which has openings 365 and contact holes 366, is formedon the passivation layer 180, and a plurality of organic light-emittingmembers 370 are formed within the openings 365.

A common electrode 270 is formed on the entire surface of the substrateincluding the partition 361 and the organic light-emitting members 370.The common electrode 270 may be made of a transparent or translucentconductive material having a good electron injection characteristic andthat does not negatively affect an organic material. Examples of theconductive materials include a 50 to 100 Å thick, single-layeredstructure of ITO, IZO, Al, and Ag, or a multi-layered structure ofCa—Ag, LiF—Al, Ca—Ba, and Ca—Ag-ITO. Because the common electrode 270 ismade of transparent or translucent conductive material, light may beemitted toward the top of the substrate 110 on which thin filmtransistors are formed.

The common electrode 270 is connected to the protrusions 123 of thevoltage auxiliary lines 122 through the contact holes 366 and theconnecting members 86. Hence, the common electrode 270, the protrusions123 of the voltage auxiliary lines 122, and the auxiliary electrode 111are connected to each other.

Such connections may permit the common electrode 270 to stably supply acommon voltage when the common electrode 270 is made of a highresistivity transparent or translucent conductive material.Consequently, the common voltage applied to the entire area of thecommon electrode 270 may be substantially uniform (i.e. without avoltage drop), to reduce cross-talk due to a luminance differencebetween pixels.

A fourth exemplary embodiment of the present invention, of whichportions are modified with respect to the above described firstembodiment of FIGS. 1 to 4, will be described below with reference toFIG. 21 and FIG. 22. The descriptions of the same elements as those ofthe above-described embodiments are omitted.

FIG. 21 is a layout view of an OLED display according to a fourthexemplary embodiment of the present invention, and FIG. 22 is asectional view taken along line XXII-XXII of FIG. 21.

Referring to FIG. 21 and FIG. 22, a first auxiliary electrode 111 a anda second auxiliary electrode 111 b are formed on an insulating substrate110. The first and second auxiliary electrodes 111 a and 111 b arespaced apart from each other by a predetermined interval and have asubstantially planar shape. The first and second auxiliary electrodes111 a and 111 b may be made of a low resistivity conductor including Al,Ag, Cu, or alloys thereof.

A blocking layer 112 is formed on the first and second auxiliaryelectrodes 111 a and 111 b.

A plurality of gate conductors that include a plurality of gate lines121, a plurality of second control electrodes 124 b, and a plurality ofvoltage auxiliary lines 122 are formed on the blocking layer 112. Thegate lines 121 include first control electrodes 124 a, and the voltageauxiliary lines 122 include protrusions 123.

The gate insulating layer 140 is formed on the gate conductors 121, 124b, and 122.

The gate insulating layer 140 and the blocking layer 112 have aplurality of contact holes 147 exposing the first auxiliary electrode111 a.

A plurality of first and second semiconductor islands 154 a and 154 bare formed on the gate insulating layer 140. A plurality of pairs offirst ohmic contact islands 163 a and 165 a and a plurality of pairs ofsecond ohmic contact islands 163 b and 165 b are formed on the first andsecond semiconductor islands 154 a and 154 b, respectively.

A plurality of data conductors, which include a plurality of data lines171, a plurality of driving voltage lines 172, and a plurality of firstand second output electrodes 175 a and 175 b, are formed on the ohmiccontacts 163 a, 163 b, 165 a, and 165 b and the gate insulating layer140. The driving voltage lines 172 are connected to the first auxiliaryelectrode 111 a though the contact holes 147.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175 b, the exposed portions of the semiconductor islands 154 aand 154 b, and the gate insulating layer 140.

The passivation layer 180 has a plurality of contact holes 182, 185 a,and 185 b exposing the end portions 179 of the data lines 171, the firstoutput electrodes 175 a, and the second output electrodes 175 b,respectively, and the passivation layer 180 and the gate insulatinglayer 140 have a plurality of contact holes 181, 184, and 186 exposingthe end portions 129 of the gate lines 121, the second controlelectrodes 124 b, and the protrusions 123 of the voltage auxiliary lines122, respectively. Furthermore, the passivation layer 180, the gateinsulating layer 140, and the blocking layer 112 have a plurality ofcontact holes 188 exposing the second auxiliary electrode 111 b.

A plurality of pixel electrodes 191, a plurality of connecting members85 and 86, and a plurality of contact assistants 81 and 82 are formed onthe passivation layer 180.

The connecting members 85 are connected to the second control electrodes124 b and the first output electrodes 175 a through the contact holes184 and 185 a, respectively.

The connecting members 86 are connected to the protrusions 123 of thevoltage auxiliary lines 122 and the second auxiliary electrodes 111 bthrough the contact holes 186 and 188, respectively.

A partition 361, which has openings 365 and contact holes 366, is formedon the passivation layer 180, and a plurality of organic light-emittingmembers 370 are formed within the openings 365.

A common electrode 270 is formed on the entire surface of the substrateincluding the partition 361 and the organic light-emitting members 370.

The common electrode 270 is connected to the protrusions 123 of thevoltage auxiliary lines 122 through the contact holes 366 and theconnecting members 86. Hence, the common electrode 270, the protrusions123 of the voltage auxiliary lines 122, and the second auxiliaryelectrode 111 b are connected to each other.

As described above, the first and second auxiliary electrodes 111 a and111 b are formed on the substrate 110, the first auxiliary electrode 111a is connected to the driving voltage lines 172, and the secondauxiliary electrodes 111 b are connected to the common electrode 270.Accordingly, a driving voltage may be applied to the driving voltagelines 172 and the first auxiliary electrode 111 a, and a common voltagemay be applied to the common electrode 270 and the second auxiliaryelectrode 111 b, so that the driving voltage and the common voltage maybe uniformly applied to all pixels. Moreover, the first and secondauxiliary electrodes 111 a and 111 b have sheet resistance. Hence, eventhough a voltage drop of the voltages applied to each of the pixels mayoccur, the voltages may not significantly vary because of compensationof the voltage drop by the sheet resistance. Accordingly, the drivingvoltage and the common voltage may be substantially uniformly applied tothe pixels, and cross-talk due to luminance difference between pixelsmay decrease.

While the first and second auxiliary electrodes and the driving voltagelines or the common electrode are shown as being connected in a displayarea, they may alternatively be connected in other areas.

According to exemplary embodiments of the present invention, by formingat least one auxiliary electrode, a driving voltage and a common voltagemay be substantially uniformly applied to the pixels, thereby decreasingcross-talk due to a luminance difference between pixels.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. An organic light-emitting diode (OLED) display, comprising: asubstrate; an auxiliary electrode disposed on the substrate; a firstsignal line disposed on the substrate; a second signal line crossing thefirst signal line; a driving voltage line disposed on the substrate; afirst thin film transistor connected to the first signal line and thesecond signal line; a second thin film transistor connected to the firstthin film transistor and the driving voltage line; a first electrodeconnected to the second thin film transistor; a second electrode facingthe first electrode; and a light-emitting member disposed between thefirst electrode and the second electrode, wherein the auxiliaryelectrode is connected to at least one of the driving voltage line andthe second electrode.
 2. The OLED display of claim 1, wherein theauxiliary electrode is disposed on a layer different from one of thedriving voltage line and the second electrode.
 3. An organiclight-emitting diode (OLED) display, comprising: a substrate; a firstauxiliary electrode disposed on the substrate; a first signal linedisposed on the substrate; a second signal line crossing the firstsignal line; a driving voltage line connected to the first auxiliaryelectrode; a first thin film transistor connected to the first signalline and the second signal line; a second thin film transistor connectedto the first thin film transistor and the driving voltage line; a firstelectrode connected to the second thin film transistor; a secondelectrode facing the first electrode; and a light-emitting memberdisposed between the first electrode and the second electrode.
 4. TheOLED display of claim 3, wherein the first auxiliary electrode isdisposed on a layer different from the driving voltage line.
 5. The OLEDdisplay of claim 3, further comprising a blocking layer disposed on thefirst auxiliary electrode.
 6. The OLED display of claim 3, wherein thefirst auxiliary electrode covers the entire surface of the substrate. 7.The OLED display of claim 3, wherein the first auxiliary electrodecomprises a transparent or translucent conductor.
 8. The OLED display ofclaim 3, wherein the first auxiliary electrode is spaced apart from thefirst signal line.
 9. The OLED display of claim 3, wherein the firstauxiliary electrode is disposed corresponding to the light-emittingmember.
 10. The OLED display of claim 9, wherein the first auxiliaryelectrode comprises at least one of Al, an Al alloy, Cu, a Cu alloy, Ag,and an Ag alloy.
 11. The OLED display of claim 3, further comprising asecond auxiliary electrode spaced apart from the first auxiliaryelectrode, the second auxiliary electrode being connected to the secondelectrode.
 12. The OLED display of claim 11, wherein the first auxiliaryelectrode and the second auxiliary electrode are disposed on the samelayer.
 13. The OLED display of claim 11, wherein the second auxiliaryelectrode receives a voltage having the same magnitude as what thesecond electrode receives.
 14. The OLED display of claim 11, furthercomprising a voltage auxiliary line disposed on the same layer as thefirst signal line or the second signal line, the voltage auxiliary linebeing connected to the second electrode and the second auxiliaryelectrode.
 15. The OLED display of claim 11, wherein the secondelectrode comprises a transparent or translucent conductor.
 16. The OLEDdisplay of claim 15, wherein the second electrode comprises indium tinoxide or indium zinc oxide.
 17. The OLED display of claim 3, furthercomprising a partition, the light-emitting member being disposed in anopening of the partition.
 18. An organic light-emitting diode (OLED)display, comprising: a substrate; an auxiliary electrode disposed on thesubstrate; a first signal line disposed on the substrate; a secondsignal line crossing the first signal line; a first thin film transistorconnected to the first signal line and the second signal line; a secondthin film transistor connected to the first thin film transistor; afirst electrode connected to the second thin film transistor; a secondelectrode facing the first electrode, the second electrode beingconnected to the auxiliary electrode; and a light-emitting memberdisposed between the first electrode and the second electrode.
 19. TheOLED display of claim 18, further comprising a voltage auxiliary linedisposed on the same layer as the first signal line or the second signalline, the voltage auxiliary line being connected to the secondelectrode.
 20. The OLED display of claim 18, wherein the secondelectrode comprises a transparent or translucent conductor.
 21. The OLEDdisplay of claim 20, wherein the second electrode comprises indium tinoxide or indium zinc oxide.